In tracked vehicles, to drive around a bend the respective track or drive wheels on the inside of the curve are made slower than the track or drive wheels on the outside of the curve.
From the prior art various systems are known in which the brake power is used, in that it is delivered to the track or drive wheels on the inside of the curve.
For example, from DE 10 2005 027 117 A1 by the present applicant an electric drive system for a vehicle with skid steering is known, which comprises two drive machines of the same type, a source of electrical energy, an electronic control device and a left-hand and a right-hand summation transmission which are made as planetary transmissions. One drive machine drives the ring gear of the summation transmission on the left, while the other drive machine drives the ring gear of the summation transmission on the right. The ring gear of the left-hand summation transmission is in drive connection, via a mechanical gear-train, directly with the gear of the right-hand summation transmission, while the ring gear of the right-hand summation transmission is in drive connection, via a second mechanical gear-train, directly with the sun gear of the left-hand summation transmission. In this it is provided that a left-hand sun gear shaft extends through a left-hand hollow shaft toward the middle of the vehicle and a right-hand sun gear shaft extends through a right-hand hollow shaft towards the middle of the vehicle. This makes for a very compact structure.
In addition, from WO 2005/039958 A1 by the present Applicant, an electric drive system for a vehicle with skid steering by a left-hand electric drive mechanism and a right-hand one of the same type is known, which has a diesel engine and generator combination as the source of electrical energy, an electronic control device for the independent control of the speeds of the two drive machines, with a summation transmission on the left and one of the same type on the right. These are made as planetary transmissions, such that the planetary carriers form the drive output and the ring gear of the left-hand summation transmission can be driven directly by the left-hand drive machine and the ring gear of the right-hand summation transmission can be driven directly by the right-hand drive machine, and the ring gear of the left-hand summation transmission is connected directly by a first mechanical gear-train to the sun gear of the right-hand summation transmission and the ring gear of the right-hand summation transmission is connected directly by a second mechanical gear-train to the sun gear of the left-hand summation transmission.
Besides the electro-mechanical drive systems, purely electric and purely mechanical drive systems are also known.
As a rule, the steering function of tracked vehicles is enabled by a “steer-by-wire” system. In this, the safety and functionality of the steering system are particularly important; above all, the entire connection from the steering wheel to the control unit and from the control unit to the electric drive must be functional.
This can be ensured by making all the components of the steering system redundant in such a manner that if an individual component fails, the overall function of the steering can still be ensured. Disadvantageously, however, it is very expensive to do that since in some cases threefold redundancy is needed in order to recognize which system is not working properly.
The purpose of the present invention is to indicate a steering system for tracked vehicles, which provides a redundant steering possibility for tracked vehicles that is activated in the event of failure of the primary steering mechanism. In addition, the steering system according to the invention should be of inexpensive and simple structure and should be capable of integration into already existing steering systems.
This fall-back level only becomes active if a failure or malfunction of the main steering system occurs, and otherwise has no function during regular operation.